Association of Perioperative β-Blockade With Mortality and Cardiovascular Morbidity Following Major Noncardiac Surgery

Abstract

ImportanceThe effectiveness of perioperative ␤-blockade in patients undergoing noncardiac surgery remains controversial.Objective To determine the associations of early perioperative exposure to ␤-blockers with 30-day postoperative outcome in patients undergoing noncardiac surgery. Design, Setting, and PatientsA retrospective cohort analysis evaluating exposure to ␤-blockers on the day of or following major noncardiac surgery among a populationbased sample of 136 745 patients who were 1:1 matched on propensity scores (37 805 matched pairs) treated at 104 VA medical centers from January 2005 through August 2010.Main Outcomes and Measures All cause 30-day mortality and cardiac morbidity (cardiac arrest or Q-wave myocardial infarction). ResultsOverall 55 138 patients (40.3%) were exposed to ␤-blockers. Exposure was higher in the 66.7% of 13 863 patients undergoing vascular surgery (95% CI, 65.9%-67.5%) than in the 37.4% of 122 882 patients undergoing nonvascular surgery (95% CI, 37.1%-37.6%; PϽ.001). Exposure increased as Revised Cardiac Risk Index factors increased, with 25.3% (95% CI, 24.9%-25.6%) of those with no risk vs 71.3% (95% CI, 69.5%-73.2%) of those with 4 risk factors or more exposed to ␤-blockers (PϽ.001). Death occurred among 1.1% (95% CI, 1.1%-1.2%) and cardiac morbidity occurred among 0.9% (95% CI, 0.8%-0.9%) of patients. In the propensity matched cohort, exposure was associated with lower mortality (relative risk [RR], 0.73; 95% CI, 0.65-0.83; PϽ.001; number need to treat [NNT], 241; 95% CI, 173-397). When stratified by cumulative numbers of Revised Cardiac Risk Index factors, ␤-blocker exposure was associated with significantly lower mortality among patients with 2 factors (RR, 0.63 [95% CI, 0.50-0.80]; PϽ.001; NNT, 105 [95% CI, 69-212]), 3 factors (RR, 0.54 [95% CI, 0.39-0.73]; PϽ.001; NNT, 41 [95% CI, 28-80]), or 4 factors or more (RR, 0.40 [95% CI, 0.25-0.73]; PϽ.001; NNT, 18 [95% CI,). This association was limited to patients undergoing nonvascular surgery. ␤-Blocker exposure was also associated with a lower rate of nonfatal Q-wave infarction or cardiac arrest (RR, 0.67 [95% CI, 0.57-0.79]; PϽ.001; NNT, 339 [95% CI,), again limited to patients undergoing nonvascular surgery.Conclusions and Relevance Among propensity-matched patients undergoing noncardiac, nonvascular surgery, perioperative ␤-blocker exposure was associated with lower rates of 30-day all-cause mortality in patients with 2 or more Revised Cardiac Risk Index factors. Our findings support use of a cumulative number of Revised Cardiac Risk Index predictors in decision making regarding institution and continuation of perioperative ␤-blockade. A multicenter randomized trial involving patients at a low to intermediate risk by these factors would be of interest to validate these observational findings.

The Revised Cardiac Risk Index in the new millennium: a single-centre prospective cohort re-evaluation of the original variables in 9,519 consecutive elective surgical patients

“…A recent large retrospective analysis of the Veterans Affairs Medical Center surgical database also failed to find diabetes as a significant predictor of cardiac outcomes. 19 Focused attempts to include modified terms related to diabetes mellitus or preoperative blood sugar levels could not significantly improve the ability to predict the risk of MCCs or improve the accuracy or the discrimination of the index. Glycosylated hemoglobin has been advocated as an important risk factor in diabetic outcomes and may be a factor that could potentially improve the index; [20][21][22] however, the data in our database were insufficient to assess this variable.…”

“…This definition does have the advantage of being the threshold for chronic kidney disease as defined by the National Kidney Foundation. 19 On the basis of these considerations, we would advocate for a 5-Factor model where the renal component is denoted by a low GFR and diabetes is dropped from the index.…”

Benefits and Harms of Beta Blockers in the Perioperative Period of Non-Cardiac Surgery: A Narrative Review

“…No significant difference was observed in vascular surgery. The overall rate of stroke was higher in the beta-blocker group (8).…”

“…Metoprolol was more frequently prescribed but the mortality rate was significantly higher in the metoprolol group compared to the atenolol group. The rate of stroke was also significantly higher in the metoprolol group (8). In 2016, Cohn noted that more cardioselective beta-blockers (atenolol or bisoprolol) had more beneficial effects than metoprolol did, and metoprolol had no beneficial effects in diabetic patients and in vascular surgery (27).…”

Predicting outcomes: Is there utility in risk scores?

“…For example, prior observational studies have suggested that perioperative beta blockers are associated with benefit in patients at higher predicted cardiac risk, while they are associated with harm in individuals at lower predicted cardiac risk. 2,3 Fourth, risk information can help specify the required intensity of perioperative monitoring, such as whether a patient warrants invasive monitoring or postoperative care in a critical care unit. The role of estimated perioperative risk in rationally choosing postoperative care settings is especially important since monitored acute care beds are expensive and often scarce resources.…”